This invention relates to reflected wave object detection systems, and more particularly to such systems in which velocity and angular misdistance are measured.
In the field of gunnery, a cannon is aimed in response to output signals from a fire control computer. A radar system measures the position and velocity of a target and provides information indicative thereof to the fire control computer. Computations performed by the fire control computer must take into account the velocity of projectiles fired from the aircraft in order to compute a lead angle. The lead angle is the angle measured from the aircraft between the position of the target at the time the measurement is made and its expected position at the time projectiles will reach the target. Present systems factor a parameter into the computations performed by the fire control computer indicative of a nominal projectile velocity. This nominal projectile velocity can differ from the actual velocity of projectiles directed from the aircraft cannon toward the target due to several causes. For example, atmospheric effects, lot differences in projectiles, cannon barrel wear and other variations can cause the actual projectile velocity to differ from the nominal velocity. Thus, the fire control computer utilizes an inaccurate indication of the projectile velocity in its computations, and errors are caused in lead angle computation. Such errors lead to an inability to hit the target, conceivably leading to disastrous results.